In most units there are some officers present. In other units there are bone at all and it is common for senior NCOs to sometimes be Unit Commanding Officers - or more formally OC - Officer in Charge
The Sea Cadets has an Officer development Programme which aims to recruit, select and train people for its key leadership positions.
This is a standardised process across the country and involves a series of phases and board interview residentials where a variety of leadership attributes are assessed.
Some officers start on the officer track. Others may have been NCOs for many years.